Structure and luminescence studies of tris(nitrato-O,O′)bis(2,2′-bipyridyl-N,N′)dysprosium(III) complex

The title compound, [Dy(NO3)3(bipy)2], is isostructural with the La, Pr, Nd, Eu and Lu analogues where bipy=2, 2′-bipyridyl. The Dy complex was crystallized in orthorhombic with space group Pbcn. The Dy(III) ion was coordinated with the two bipy ligands and three nitrate anions giving a ten coordination number. Measurements of the molar conductance in ethanol and water solutions indicate that the complex is non-electrolyte. A comparative study of the emission of [Dy(NO3)3(bipy)2] complex with those of the adduct mixture of bipy and Dy at a 1:1 ratio, has been investigated. In the solid state, photoluminescence (PL) spectrum of the complex had sharp emission bands corresponding to the 4F9/2→6H15/2 (476.5 and 482 nm), 4F9/2→6H13/2(572.6 and 573.8 nm), 4F9/2→6H11/2 (661.6 nm) and 4H3/2→6H15/2 (961.0 nm) transitions. The hypersensitive peak of the complex has the yellow emission stronger than the blue emission in the solid state as well as in the solution. The complex has a good thermal stability due to the role of π–π interactions stacking.